ABN Lookup
Look up any ABN instantly — name, status, GST and ACN — with no captcha, and see how the 11-digit checksum works.
Updated 2026-06-30 · Official source: abr.business.gov.au · Live data from the Australian Business Register
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An Australian Business Number (ABN) is the 11-digit identifier the Australian Business Register (ABR) issues to every business and entity in Australia. You will check one constantly: to confirm a supplier is a real, active business, to see whether they are registered for GST, and to avoid the requirement to withhold 47% from a payment when a supplier has not quoted a valid ABN.
This tool looks up an ABN instantly — no captcha — and shows the entity name, ABN status, GST registration and any business names. It also runs the official modulus-89 checksum in your browser so a mistyped ABN is caught immediately, and decodes the number so you can see how the ACN sits inside it.
How to look up an ABN
- 1
Enter the ABN
Type the 11-digit number with or without spaces. The decoder normalises it and checks the modulus-89 checksum as you type.
- 2
Or search by name
Don't have the number? Use the by-name search to find a business or entity in the ABR and read off its ABN.
- 3
Read the live result
A lookup returns the entity name, whether the ABN is active or cancelled, GST registration and date, and any registered business names.
- 4
Check the GST status before invoicing
Confirm the supplier is registered for GST before you claim a GST credit — the result shows it plainly.
What each digit of an ABN means
An ABN is 11 digits. The first two are check digits; the remaining nine are the identifier. For a company, those nine digits are its ACN (Australian Company Number) — so an ABN is effectively the ACN with a two-digit prefix and checksum. Here is a valid ABN broken down:
- Check digits:
- Two-digit modulus-89 checksum
- Identifier:
- For companies, these nine digits are the ACN
How the modulus-89 checksum works
Subtract 1 from the first digit, multiply each of the 11 digits by the weights 10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and add the results. If the total divides evenly by 89, the ABN is internally valid. This is what lets the tool flag a transposed digit instantly, before it ever contacts the ABR. A number can pass this check and still be cancelled, so the live status matters.
ABN vs ACN — what's the difference?
An ACN is the 9-digit number ASIC issues when a company is registered. An ABN is the 11-digit number the ABR issues to any business — sole traders, partnerships, trusts and companies. When a company gets an ABN, its 11-digit ABN is built from its 9-digit ACN plus a two-digit checksum prefix, which is why you can read the ACN straight out of a company's ABN.
GST registration and the $75,000 threshold
A business must register for GST once its annual turnover reaches A$75,000 (A$150,000 for non-profits). The lookup shows whether the supplier is currently registered for GST and from what date. This matters because you can only claim a GST credit on a purchase from a supplier who is registered — and if a supplier doesn't quote a valid ABN, you may have to withhold 47% of the payment under the no-ABN withholding rule.
Reading the result
Active means the ABN is current on the register, with the entity name and GST status shown. Not active means it has been cancelled. Format checked (amber) means the ABR could not be reached at that moment, so only the format and checksum were verified — try again shortly.
How this compares to the official ABN Lookup
The ABR holds the data and we use it. Where we win is speed, friction and the explainer content the official tool doesn't carry.
| Entity name, status & GST | Yes | Yes |
|---|---|---|
| No captcha / instant | Yes | Sometimes gated |
| Modulus-89 checksum (catches typos) | Yes | No |
| Digit-by-digit decode | Yes | No |
| ABN ↔ ACN explainer | Yes | No |
| Search by name | Yes | Yes |
| Works offline as a format check | Yes | No |